Everything seemed to be on track. American prisoners were released. Compliments were exchanged. The place and date were even set. But now the summit between the U.S. and North Korea is not necessarily a done deal. North Korean officials have threatened to walk away from the talks. The North Korean government released a statement taking aim at recent comments made by National Security Adviser John Bolton, who suggested on Sunday that North Korea could follow the model of Libya - when Libya's leader Moammar Gadhafi surrendered all his nuclear capabilities. And, of course, then he ended up dying at the hands of his own people. So what does this latest move by North Korea mean for these fragile negotiations? We're going to put that question to Republican Senator Cory Gardner of Colorado. He sits on the Senate Foreign Relations Committee.

Senator, thanks for being back on the show.

CORY GARDNER: Good morning. Thanks for having me.

MARTIN: Do you think John Bolton was being intentionally provocative when he made those remarks...

GARDNER: No, I don't...

MARTIN: ...I mean, suggesting that Libya was the model for North Korea? He had to have known that would be perceived as provocative by the North.

GARDNER: I don't think so. And obviously, we've been here before. And with higher hopes in these North Korea talks come the possibility for higher disappointment because the Kim Jong Un family has had a history of propaganda and then disappointment, where they set up the possibility of denuclearization or promises, and then they break those promises. That seems to be what they're talking about doing again. Now, I hope that we can continue forward with the conversation that seems to be taking place. Kim Jong Un has said he supports denuclearization. But this is fragile. And we've known all along, cautious optimism had to be called for. But let's hope this turns out differently than at least it appears in the statement last night.

MARTIN: You told The Daily Beast that there shouldn't even be a summit if there's no, as you just said, verifiable, irreversible path to denuclearization. So you clearly think that should be a precondition for these talks. You've been talking with President Trump about this. Does he agree with you?

GARDNER: Absolutely. He agrees. And, you know, yesterday, I learned that this summit may be more than just a day summit. In our conversation with the president yesterday, he talked about how this summit could go on for more than one day if it's productive. And I think that's something that no one has heard before. And so we are on the cusp of possibly attaining something that would be very positive for the world - denuclearization of the Korean Peninsula.

But at this fragile state that we're in right now with Kim Jong Un trying to rearrange the deck, so to speak - the chairs on the decks, so to speak - is a setback in a way. It's not a surprise. And it's certainly not insurmountable going forward. But if President Trump or any of our administrative officials or those who have had conversations with the North Korean regime get any sense, any scintilla that this isn't going to be denuclearization, there's no reason for this meeting to occur but instead a full backing of maximum pressure doctrine - our doctrine to implement sanctions economically as well as diplomatic isolation - must continue in full force.

MARTIN: But then where are we? Because you say that it's a precondition for the talks that they have to promise for denuclearization. But North Korea issued a statement saying that it's not going to agree to denuclearization unless the U.S. stops - and this is their word - blackmailing the North.

GARDNER: Well, this seems to be that North Korea may be having two different spokespeople make these statements because it wasn't that long ago that Kim Jong Un understood the need for these exercises. These exercises have been going on for years. No invasion has occurred. It's simply a ploy or propaganda, again, by North Korea to put fear into the people of North Korea. And this is...

MARTIN: We should just say that this - they also took issue with these joint military exercises that the U.S. conducted with South Korea.

GARDNER: Right. Yeah, the joint military exercises have been going on with South Korea for a very long time, and they're not a surprise. And it wasn't that long ago that Kim Jong Un said that there was no problem with these exercises. He understood the need for them. They weren't going to call for them being scaled back. And so all of a sudden, it's almost as if somebody had been on vacation for the past several months, somebody else came back into work and started picking up the old work that they'd been doing in terms of slamming these exercises because that's a different thing that had happened over the past several months.

MARTIN: Let me ask you, though, in seconds remaining - I mean, these are negotiations. You got to give and take. So what concession is the U.S. willing to make in this?

GARDNER: Well, I think if you look at the Olympics - I mean, North Korea was invited to participate in the Olympics. Exercises were delayed and postponed. I think that's a good-faith effort. My gosh, the president of the United States is going to be meeting possibly with Kim Jong Un. That's the highest diplomatic offering this country has. And that's a very significant step. And so I'm not exactly sure what Kim Jong Un wants other than to continue the propaganda that they have where they try to get empathy from the world and then turn around, break the deal. And here we are again with the hermit kingdom continuing to be as isolated as they have been.

MARTIN: Senator Cory Gardner of Colorado. He's a member of the Foreign Relations Committee, chair of the subcommittee on East Asia, as well. Thanks so much for your time this morning, Senator.